Various user input devices such as optical pointing devices, touchscreens, rocker switches, and other mechanisms enable capturing user control inputs for controlling an electronic device. One type of user input device is a capacitive input device, which relies on tracking changes in charge at one or more pairs of capacitively coupled conductive elements. A relative change in the charge, based on a user manipulation at the capacitive input device, generally corresponds to an intended user control input at an electronic device.
Unfortunately, capacitive input devices are negatively affected by electromagnetic noise or interference emanating from other circuitry within or near the electronic device, as well as by wireless communications occurring adjacent the capacitive input device. In particular, electromagnetic noise causes a change in the charge being tracked at the capacitively coupled conductive elements of the capacitive input device. This change caused by noise becomes erroneously interpreted as an intended user control input to the electronic device. Accordingly, a function of the electronic device is triggered or modified by the electromagnetic interference in a manner that does not actually correspond with an intended user control input.
Users of electronic devices expect precision and accuracy in capturing their intended control of the portable electronic device. Conventional attempts by designers and manufacturers of electronic devices to reduce the impact of electromagnetic noise, such as conventional shielding and filtering mechanisms, have fallen short of effectively counteracting the presence of electromagnetic noise during use of capacitive input devices.